A novel fluidized bed respirometric technique for determination of in situ biofilm kinetics

Nabin Chowdhury, George Nakhla, Jesse Zhu

Research output: Journal PublicationArticlepeer-review

2 Citations (Scopus)


A respirometric approach has been developed to determine heterotrophic biofilm kinetics using fluidized bioparticles - particles with attached biomass. Lava rock particles of 600 m were used as a biomass carrier medium. The modified respirometer successfully estimates in situ biofilm kinetics of the bioparticles collected from a pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor. The observed maximum specific growth rates (μmax) of 3.69 ± 0.44d-1 and biomass yields (YH) of 0.36 ± 0.03g COD/g COD in the fluidized bed respirometers were significantly different from the μmax of 5.57-5.72d1 and YH of 0.54-0.59g COD/g COD observed in the conventional respirometric tests for bioparticles and detached biomass. The higher Monod half-saturation coefficient (KS) of 186-219mg COD/L observed in the fluidized bed respirometers relative to the 49-58mg COD/L in the conventional respirometers reveals the presence of mass transfer resistance in the LSCFB despite fluidization. Significantly reduced yields in the fluidized bed respirometers and the estimated maintenance coefficient of 1.16d -1 for the particulate biofilm in the LSCFB clearly emphasize that a substantial amount of substrate was utilized for cell maintenance at the low food to microorganism (S/X) ratio of 0.5g COD/g VSS.

Original languageEnglish
Pages (from-to)455-465
Number of pages11
JournalEnvironmental Technology (United Kingdom)
Issue number4
Publication statusPublished - 1 Feb 2012
Externally publishedYes


  • biokinetics
  • diffusion
  • fixed-film respirometry
  • food to microorganism ratio
  • maintenance coefficient

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal


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